1. Field of the Invention
This invention relates to cleansing bar compositions, which are clear and exhibit exceptionally low ocular and skin irritation. The cleansing bar compositions have good foaming properties.
2. Description Of The Prior Art
Conventional soap bars are opaque and have several problems associated with them. One problem associated with soap bars is that they tend to absorb water on the surface of the bar and form a gel or mush on the wet surfaces. The gel or mush tends to rinse off the bar upon use and go down the bath or sink drain, resulting in a less efficient soap bar.
Another problem associated with soap bars is that cracks form in the soap bars upon drying after use. The cracks lead to part of the soap bar falling off, usually going down the bath or sink drain, and ultimately a less efficient soap bar.
Many people also find conventional soap bar compositions to be irritating to their eyes. Therefore, there is a need for a cleansing bar that does not form gel or mush, does not crack upon drying, and is not irritating to the eyes.
U.S. Pat. No. 5,286,755 discloses a non-alcoholic cosmetic gel comprising a polyol, a dibenzylidene-ose, a sulfosuccinate hardening agent, and water. The compositions may contain surfactants conventionally employed in cosmetics. The reference does not address the issue of eye irritation and is silent as to suitable genus and species of surfactants for cleansing bar applications.
Despite the disclosure of the prior art, there is a continuing need for a cleansing bar that does not form gel or mush, does not crack upon drying, and is not irritating to the eyes.
It is therefore, the object of the present invention to provide a cleansing bar that does not form gel or mush, does not crack upon drying, and is not irritating to the eyes.
The present invention provides a clear cleansing bar composition including: a) from about 0.5% to about 30% of at least one amphoteric surfactant; b) from about 0.5% to about 30% of at least one anionic surfactant; c) from about 0.5% to about 30% of at least one non-ionic surfactant; d) from about 0. 1% to about 20% of a solidifying agent; and e) from about 10% to about 90% of at least one organic solvent; wherein the composition is not irritating to the eyes.
The compositions of the present invention contain at least one amphoteric surfactant. As used herein, the term xe2x80x9camphotericxe2x80x9d means: 1) molecules that contain both acidic and basic sites such as, for example, an amino acid containing both amino (basic) and acid (e.g., carboxylic acid, acidic) functional groups; or 2) zwitterionic molecules which possess both positive and negative charges within the same molecule. The charges of the latter may be either dependent on or independent of the pH of the composition. Examples of zwitterionic materials include, but are not limited to, alkyl betaines and amidoalkyl betaines. The amphoteric surfactants are disclosed herein without a counter ion. One skilled in the art would readily recognize that under the pH conditions of the compositions of the present invention, the amphoteric surfactants are either electrically neutral by virtue of having balancing positive and negative charges, or they have counter ions such as alkali metal, alkaline earth, or ammonium counter ions.
Commercially available amphoteric surfactants suitable for use in the present invention include, but are not limited to amphocarboxylates, alkyl betaines, amidoalkyl betaines, amidoalkyl sultaines, amphophosphates, phosphobetaines, pyrophosphobetaines, carboxyalkyl alkyl polyamines, and mixtures thereof. Cocamidopropylbetaine, lauroamphoglycinate, lauric-myristic phosphobetaines, and lauryl betaine are preferred. The amount of amphoteric surfactant may range from about 0.5% to about 30%, preferably from about 1% to about 20% by weight of the total composition.
The compositions of the present invention also contain at least one anionic surfactant. Suitable anionic surfactants include, but are not limited to alkyl sulfates; alkyl ether sulfates; alkyl monoglyceryl ether sulfates; alkyl monoglyceride sulfates; alkyl monoglyceride sulfonates; alkyl sulfonates; alkylaryl sulfonates; alkyl sulfosuccinates; alkyl ether sulfosuccinates; alkyl sulfosuccinamates; alkyl amidosulfosuccinates; alkyl carboxylates; alkyl amidoethercarboxylates; alkyl succinates; fatty acyl sarcosinates; fatty acyl amino acids; fatty acyl taurates; fatty alkyl sulfoacetates; alkyl phosphates; and mixtures thereof, wherein the alkyl group has from about 10 to about 16 carbon atoms. Preferred anionic surfactants include sodium laureth sulfate and sodium laureth-13 carboxylates. The amount of anionic surfactant may range from about 0.5% to about 30%, preferably from about 1% to about 20% by weight of the total composition.
Nonionic surfactants are also utilized in the compositions of the present invention. One class of nonionic surfactants useful in the present invention are polyoxyethylene derivatives of polyol esters, wherein the polyoxyethylene derivative of polyol ester (1) is derived from (a) a fatty acid containing from about 8 to about 22, and preferably from about 10 to about 14 carbon atoms, and (b) a polyol selected from sorbitol, sorbitan, glucose, xcex1-methyl glucoside, polyglucose having an average of about 1 to about 3 glucose residues per molecule, glycerine, pentaerythritol and mixtures thereof, (2) contains an average of from about 10 to about 120, and preferably about 20 to about 80 oxyethylene units; and (3) has an average of about 1 to about 3 fatty acid residues per mole of polyoxyethylene derivative of polyol ester.
Examples of preferred polyoxyethylene derivatives of polyol esters include, but are not limited to PEG-80 sorbitan laurate and Polysorbate 20. PEG-80 sorbitan laurate, which is a sorbitan monoester of lauric acid ethoxylated with an average of about 80 moles of ethylene oxide, is available commercially from ICI Surfactants of Wilmington, Delaware under the tradename, xe2x80x9cAtlas G-4280.xe2x80x9d Polysorbate 20, which is the laurate monoester of a mixture of sorbitol and sorbitol anhydrides condensed with approximately 20 moles of ethylene oxide, is available commercially from ICI Surfactants of Wilmington, Delaware under the tradename xe2x80x9cTween 20.xe2x80x9d
Another class of suitable nonionic surfactants includes long chain alkyl glucosides or polyglucosides, which are the condensation products of (a) a long chain alcohol containing from about 6 to about 22, and preferably from about 8 to about 14 carbon atoms, with (b) glucose or a glucose-containing polymer. The alkyl glucosides have about 1 to about 6 glucose residues per molecule of alkyl glucoside. The preferred nonionic surfactants include Polysorbate 20 and Polyoxyethylene-Sorbitan Laurate. The amount of nonionic surfactant may range from about 0.5% to about 30%, preferably from about 1% to about 20% by weight of the total composition.
The compositions of the invention may include a cationic surfactant. Useful cationic surfactants include N-alkyl betaines, quaternary ammonium compounds, amido-amines, N-alkylamines, N-alkylamine oxides, amido-amine betaines, amido-amine salts, amido-amine oxides, sultaines and ethoxylated amines. The amount of cationic surfactant may range from about 0.1% to about 10% by weight of the total composition.
The present invention requires a solidifying agent in order to make soap bars. The solidifying agent may be selected from the group consisting of dibenzylidene alditols (such as sorbitol, xylitol, ribitol), and mixtures thereof. The solidifying agent is present in the cleansing bar at a concentration of from about 0.1% to about 20%, preferably from about 0.5% to about 5% by weight of the total composition.
At least one organic solvent is utilized in the compositions of the present invention. Suitable organic solvents include, but are not limited to dihydroxy aliphatic alcohols containing from 3 to 6 carbon atoms, such as 1,3 propylene glycol, 1,3-butylene glycol, 1,4 butylene glycol and hexylene glycol; polyethylene and polypropylene glycols, such as dipropylene glycol, tripropylene glycol, tetrapropylene glycol and 1,3-propanediol; monohydric alcohols, such as ethanol and propanol; polyhydric alcohols, such as glycerol, diglycerol, and polyglycerol; and mixtures thereof. Preferably, the organic solvent is a mixture of dihydroxy and polyhydric alcohols. The amount of organic solvent may range from about 10% to about 90%, preferably from about 20% to about 80% by weight of the total composition.
The compositions of the present invention optionally contain a solidifying synergist. The solidifying synergist aids the solidifying agent in forming a solid soap bar. Suitable solidifying synergists include, but are not limited to cellulose and guar derivatives, including but not limited to hydroxypropylcellulose, acrylic acid polymers, polyacrylamides, alkylene/alkylene oxide polymers, smectite hydrophilic and organoclays, hydrated and fumed silicas, gelatin, keratin, xanthan and guar gums, carrageenan, agar and alginates. When utilized, the amount of solidifying synergist utilized may range from about 0.05% to about 10%, preferably from about 0.1% to about 5% by weight of the total composition.
Optional ingredients may be incorporated into the composition of this invention. These ingredients include perfumes, colorants and dyes, beads, antimicrobial agents, and insect repellent agents.
The clear soap bar compositions according to the invention may be prepared by means known in the art. In a preferred embodiment, the soap bars are prepared by mixing and heating at least one organic solvent as described above to about 70xc2x0 C. to about 130xc2x0 C., when utitilized, the solidifying synergist described above is added and mixing is continued until a clear mucillage is formed. The solidifying agent described above is then added and mixed until fully dissolved. To this mixture is added surfactant(s) and mixed. Optional ingredients like perfume and colorants are added when temperature reaches below about 90xc2x0 C. The molten stock is then poured into suitable molds of different forms made of plastic or rubber and allowed to cool and harden at ambient conditions. The soap bar compositions may be aerated such that the soap bar will float in water. The clear soap bar may be formed around a small toy.